where /htdocs/www/dirname is the full path to the directory that you are trying to delete. Doing that will show you all the hidden files inside the directory. You can then delete the hidden file individually like this:

rm -f /htdocs/www/dirname/.hiddenfile

Or you can just delete the entire directory without regard to what is still inside it by typing:

rm -rf /htdocs/www/dirname

2) To delete a directory that still has hidden files in it with your FTP program, first turn on your ability to see hidden files with your FTP program. Then click on the revealed hidden file and delete it with your FTP program as you normally would any other file. When you've gotten rid of all the hidden files, you will be able to delete the directory that they were under.